Turkey today described a scheduled visit by an Iraqi delegation as "a final chance" for diplomacy amid reports of further clashes between Kurdish fighters and Turkish troops.

The Iraqi team, being led by the defence minister, General Abdel Qader Jassim, includes members of northern Iraq's Kurdish administration.

As the two sides prepared for talks aimed at averting a ground invasion of northern Iraq, the Turkish president, Abdullah Gul, warned that his country's patience was running out.

"Although we respect the territorial integrity and unity of Iraq, Turkey is running out of patience and will not tolerate the use of Iraqi soil for the purpose of terrorist activities," he said.

Turkish security officials have confirmed a series of sorties by warplanes and ground troops into Iraqi territory since Sunday, although Ankara has said it would exhaust all diplomatic efforts before any invasion.

In the latest skirmish, Turkish officials said troops using tanks and artillery had repelled an attack by up to 40 rebels from the Kurdistan Workers party (PKK) on a military post in Hakkari province near the border late yesterday.

Turkey's military and civilian leaders yesterday recommended the government first take economic measures "against those groups directly or indirectly supporting the separatist terrorist organisation in the region".

The self-ruling Kurdish administration in northern Iraq relies heavily on Turkish investment, mainly for construction, including the building of roads, hospitals and infrastructure.

The Turks also sell electricity to northern Iraq, and most food sold in markets there comes from Turkey.

As Turkey's commanders continued to weigh up their options, it emerged that the weather could be a decisive factor.

With the onset of winter, rain and snow could hamper the movement of tanks and helicopters in what is already difficult terrain. The onset of cold weather also means PKK fighters have less scope to move around when snow blocks mountain passes.

Turkey has massed as many as 100,000 troops along the mountainous border ahead of a possible cross-border operation to crush around 3,000 PKK fighters using northern Iraq as a base from which to launch raids into Turkey.

A Kurdish ambush that led to the death of 12 soldiers at the weekend inflamed Turkish public opinion, intensifying the pressure on the government to take decisive military action.

The US has expressed its alarm at such a prospect, urging Turkey to desist from a military strike that could destabilise one of Iraq's few peaceful regions.

The US secretary of state, Condoleezza Rice is to visit Turkey early next month to try to reduce tensions between Ankara and Iraq. The Turkish prime minister, Tayyip Erdogan, is also due to meet the US president, George Bush, in Washington a few days afterwards.

Ms Rice told the House foreign affairs committee yesterday she had told Mr Erdogan in a phone conversation on Sunday that she took the situation "extremely seriously".

Kurkish officials claim Turkey is using the PKK as a pretext to weaken a powerful Kurdish entity on its border.

Kurds argue that Turkey should overcome its "paranoia" that an independent Iraqi Kurdistan would encourage Turkey's own Kurds to secede, taking with them chunks of the territory saved from European dismemberment by Mustafa Kemal Ataturk, modern Turkey's founder.